The patch titled
uml: irq locking commentary
has been added to the -mm tree. Its filename is
uml-irq-locking-commentary.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: uml: irq locking commentary
From: Jeff Dike <jdike@xxxxxxxxxxx>
Locking commentary.
Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxxxxxx>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/um/kernel/irq.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff -puN arch/um/kernel/irq.c~uml-irq-locking-commentary arch/um/kernel/irq.c
--- a/arch/um/kernel/irq.c~uml-irq-locking-commentary
+++ a/arch/um/kernel/irq.c
@@ -78,6 +78,14 @@ skip:
return 0;
}
+/*
+ * This list is accessed under irq_lock, except in sigio_handler,
+ * where it is safe from being modified. IRQ handlers won't change it -
+ * if an IRQ source has vanished, it will be freed by free_irqs just
+ * before returning from sigio_handler. That will process a separate
+ * list of irqs to free, with its own locking, coming back here to
+ * remove list elements, taking the irq_lock to do so.
+ */
static struct irq_fd *active_fds = NULL;
static struct irq_fd **last_irq_ptr = &active_fds;
@@ -243,6 +251,7 @@ void free_irq_by_fd(int fd)
free_irq_by_cb(same_fd, &fd);
}
+/* Must be called with irq_lock held */
static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
{
struct irq_fd *irq;
@@ -308,6 +317,12 @@ void deactivate_fd(int fd, int irqnum)
ignore_sigio_fd(fd);
}
+/*
+ * Called just before shutdown in order to provide a clean exec
+ * environment in case the system is rebooting. No locking because
+ * that would cause a pointless shutdown hang if something hadn't
+ * released the lock.
+ */
int deactivate_all_fds(void)
{
struct irq_fd *irq;
_
Patches currently in -mm which might be from jdike@xxxxxxxxxxx are
uml-delete-unused-code.patch
uml-formatting-fixes.patch
uml-host_info-tidying.patch
uml-mark-tt-mode-code-for-future-removal.patch
uml-print-coredump-limits.patch
uml-handle-block-device-hotplug-errors.patch
uml-driver-formatting-fixes.patch
uml-driver-formatting-fixes-fix.patch
uml-network-interface-hotplug-error-handling.patch
array_size-check-for-type-uml-fix.patch
uml-fix-prototypes.patch
uml-move-sigio-testing-to-sigioc.patch
uml-create-archh.patch
uml-create-as-layouth.patch
uml-move-remaining-useful-contents-of-user_utilh.patch
uml-remove-user_utilh.patch
uml-add-missing-__init-declarations.patch
remove-unused-header-file-arch-um-kernel-tt-include-mode_kern-tth.patch
uml-speed-up-exec.patch
uml-no-locking-needed-in-tlsc.patch
uml-tidy-processc.patch
uml-remove-page_size.patch
uml-kernel_thread-shouldnt-panic.patch
uml-tidy-fault-code.patch
uml-kernel-segfaults-should-dump-proper-registers.patch
uml-comment-early-boot-locking.patch
uml-irq-locking-commentary.patch
sys_futex64-allows-64bit-futexes-workaround-for-uml.patch
utrace-uml-make-uml-compile-with-utrace-enabled.patch
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